Academic Commons Search Resultshttps://academiccommons.columbia.edu/catalog?action=index&controller=catalog&f%5Bpub_date_facet%5D%5B%5D=2011&f%5Bsubject_facet%5D%5B%5D=Ecology&format=rss&fq%5B%5D=has_model_ssim%3A%22info%3Afedora%2Fldpd%3AContentAggregator%22&q=&rows=500&sort=record_creation_date+desc
Academic Commons Search Resultsen-usBiophysical and Socioeconomic Factors Associated with Forest Transitions at Multiple Spatial and Temporal Scaleshttps://academiccommons.columbia.edu/catalog/ac:179521
Yackulic, Charles B.; Fagan, Matthew; Jain, Meha; Jina, Amir; Lim, Yili; Marlier, Miriam E.; Muscarella, Robert; Adame, Patricia; DeFries, Ruth S.; Uriarte, Mariahttp://dx.doi.org/10.7916/D8BZ64Q4Mon, 10 Nov 2014 13:12:22 +0000Forest transitions (FT) occur when socioeconomic development leads to a shift from net deforestation to reforestation; these dynamics have been observed in multiple countries across the globe, including the island of Puerto Rico in the Caribbean. Starting in the 1950s, Puerto Rico transitioned from an agrarian to a manufacturing and service economy reliant on food imports, leading to extensive reforestation. In recent years, however, net reforestation has leveled off. Here we examine the drivers of forest transition in Puerto Rico from 1977 to 2000 at two subnational, nested spatial scales (municipality and barrio) and over two time periods (1977-1991 and 1991-2000). This study builds on previous work by considering the social and biophysical factors that influence both reforestation and deforestation at multiple spatial and temporal scales. By doing so within one analysis, this study offers a comprehensive understanding of the relative importance of various social and biophysical factors for forest transitions and the scales at which they are manifest. Biophysical factors considered in these analyses included slope, soil quality, and land-cover in the surrounding landscape. We also considered per capita income, population density, and the extent of protected areas as potential factors associated with forest change. Our results show that, in the 1977-1991 period, biophysical factors that exhibit variation at municipality scales (~100 km²) were more important predictors of forest change than socioeconomic factors. In this period, forest dynamics were driven primarily by abandonment of less productive, steep agricultural land in the western, central part of the island. These factors had less predictive power at the smaller barrio scale (~10 km²) relative to the larger municipality scale during this time period. The relative importance of socioeconomic variables for deforestation, however, increased over time as development pressures on available land increased. From 1991-2000, changes in forest cover reflected influences from multiple factors, including increasing population densities, land development pressure from suburbanization, and the presence of protected areas. In contrast to the 1977-1991 period, drivers of deforestation and reforestation over this second interval were similar for the two spatial scales of analyses. Generally, our results suggest that although broader socioeconomic changes in a given region may drive the demand for land, biophysical factors ultimately mediate where development occurs. Although economic development may initially result in reforestation due to rural to urban migration and the abandonment of agricultural lands, increased economic development may lead to deforestation through increased suburbanization pressures.Ecology, Forestrymj2415, mem2225, rm2824, rd2402, mu2126Ecology, Evolution, and Environmental BiologyArticlesHigh-yield oil palm expansion spares land at the expense of forests in the Peruvian Amazonhttps://academiccommons.columbia.edu/catalog/ac:179485
Gutiérrez-Vélez, Victor Hugo; Padoch, Christine; DeFries, Ruth S.; Uriarte, Maria; Pinedo-Vasquez, Miguel Angel; Baethgen, Walter E.; de Avila Fernandes, Katia; Lim, Yilihttp://dx.doi.org/10.7916/D8ZW1JMRMon, 10 Nov 2014 10:59:57 +0000High-yield agriculture potentially reduces pressure on forests by requiring less land to increase production. Using satellite and field data, we assessed the area deforested by industrial-scale high-yield oil palm expansion in the Peruvian Amazon from 2000 to 2010, finding that 72% of new plantations expanded into forested areas. In a focus area in the Ucayali region, we assessed deforestation for high- and smallholder low-yield oil palm plantations. Low-yield plantations accounted for most expansion overall (80%), but only 30% of their expansion involved forest conversion, contrasting with 75% for high-yield expansion. High-yield expansion minimized the total area required to achieve production but counter-intuitively at higher expense to forests than low-yield plantations. The results show that high-yield agriculture is an important but insufficient strategy to reduce pressure on forests. We suggest that high-yield agriculture can be effective in sparing forests only if coupled with incentives for agricultural expansion into already cleared lands.Ecology, Agriculture, Environmental management, Deforestationvhg2103, cp32, rd2402, mu2126, map57, web2103, ka2157Center for Environmental Sustainability, International Research Institute for Climate and Society, Ecology, Evolution, and Environmental BiologyArticlesDisentangling the drivers of reduced long-distance seed dispersal by birds in an experimentally fragmented landscapehttps://academiccommons.columbia.edu/catalog/ac:179435
Uriarte, Maria; Anciães, Marina; Da Silva, Mariana T.B.; Rubim, Paulo; Johnson, Erik; Bruna, Emilio M.http://dx.doi.org/10.7916/D8C827ZDSat, 08 Nov 2014 18:28:11 +0000Seed dispersal is a crucial component of plant population dynamics. Human landscape modifications, such as habitat destruction and fragmentation, can alter the abundance of fruiting plants and animal dispersers, foraging rates, vector movement, and the composition of the disperser community, all of which can singly or in concert affect seed dispersal. Here, we quantify and tease apart the effects of landscape configuration, namely, fragmentation of primary forest and the composition of the surrounding forest matrix, on individual components of seed dispersal of Heliconia acuminata, an Amazonian understory herb. First we identified the effects of landscape configuration on the abundance of fruiting plants and six bird disperser species. Although highly variable in space and time, densities of fruiting plants were similar in continuous forest and fragments. However, the two largest-bodied avian dispersers were less common or absent in small fragments. Second, we determined whether fragmentation affected foraging rates. Fruit removal rates were similar and very high across the landscape, suggesting that Heliconia fruits are a key resource for small frugivores in this landscape. Third, we used radiotelemetry and statistical models to quantify how landscape configuration influences vector movement patterns. Bird dispersers flew farther and faster, and perched longer in primary relative to secondary forests. One species also altered its movement direction in response to habitat boundaries between primary and secondary forests. Finally, we parameterized a simulation model linking data on fruit density and disperser abundance and behavior with empirical estimates of seed retention times to generate seed dispersal patterns in two hypothetical landscapes. Despite clear changes in bird movement in response to landscape configuration, our simulations demonstrate that these differences had negligible effects on dispersal distances. However, small fragments had reduced densities of Turdus albicollis, the largest-bodied disperser and the only one to both regurgitate and defecate seeds. This change in Turdus abundance acted together with lower numbers of fruiting plants in small fragments to decrease the probability of long-distance dispersal events from small patches. These findings emphasize the importance of foraging style for seed dispersal and highlight the primacy of habitat size relative to spatial configuration in preserving biotic interactions.Ecology, Plant sciencesmu2126Ecology, Evolution, and Environmental BiologyArticlesWho is the new sheriff in town regulating boreal forest growth?https://academiccommons.columbia.edu/catalog/ac:172163
Williams, A. Park; Xu, Chonggang; McDowell, Nate G.http://dx.doi.org/10.7916/D8X34VH1Fri, 28 Mar 2014 15:40:07 +0000Climate change appears to be altering boreal forests. One recently observed symptom of these changes has been an apparent weakening of the positive relationship between high-latitude boreal tree growth and temperature at some sites (D'Arrigo et al 2008). This phenomenon is referred to as the 'divergence problem' or 'divergence effect' and is thought to reflect a non-linear relationship between temperature and tree growth, where recent warming has allowed other factors besides growing-season temperature to emerge as dominant regulators of annual growth rates.Climate change, Plant biology, Ecologyapw2134Lamont-Doherty Earth ObservatoryArticlesExploring Demographic, Physical, and Historical Explanations for the Genetic Structure of Two Lineages of Greater Antillean Batshttps://academiccommons.columbia.edu/catalog/ac:164045
Muscarella, Robert; Murray, Kevin L.; Ortt, Derek; Russell, Amy L.; Fleming, Theodore H.http://hdl.handle.net/10022/AC:P:21298Wed, 07 Aug 2013 16:10:18 +0000Observed patterns of genetic structure result from the interactions of demographic, physical, and historical influences on gene flow. The particular strength of various factors in governing gene flow, however, may differ between species in biologically relevant ways. We investigated the role of demographic factors (population size and sex-biased dispersal) and physical features (geographic distance, island size and climatological winds) on patterns of genetic structure and gene flow for two lineages of Greater Antillean bats. We used microsatellite genetic data to estimate demographic characteristics, infer population genetic structure, and estimate gene flow among island populations of Erophylla sezekorni/E. bombifrons andMacrotus waterhousii (Chiroptera: Phyllostomidae). Using a landscape genetics approach, we asked if geographic distance, island size, or climatological winds mediate historical gene flow in this system. Samples from 13 islands spanning Erophylla's range clustered into five genetically distinct populations. Samples of M. waterhousii from eight islands represented eight genetically distinct populations. While we found evidence that a majority of historical gene flow between genetic populations was asymmetric for both lineages, we were not able to entirely rule out incomplete lineage sorting in generating this pattern. We found no evidence of contemporary gene flow except between two genetic populations of Erophylla. Both lineages exhibited significant isolation by geographic distance. Patterns of genetic structure and gene flow, however, were not explained by differences in relative effective population sizes, island area, sex-biased dispersal (tested only for Erophylla), or surface-level climatological winds. Gene flow among islands appears to be highly restricted, particularly for M. waterhousii, and we suggest that this species deserves increased taxonomic attention and conservation concern.Conservation biology, Ecologyrm2824Ecology, Evolution, and Environmental BiologyArticlesTissue and skeletal changes in the scleractinian coral Stylophora pistillata Esper 1797 under phosphate enrichmenthttps://academiccommons.columbia.edu/catalog/ac:152860
Godinot, Catherine; Ferrier-Pages, Christine; Montagna, Paolo; Grover, Renaudhttp://hdl.handle.net/10022/AC:P:14778Wed, 26 Sep 2012 17:00:51 +0000Long-term phosphate enrichments (0, 0.5, and 2.5 μmol L− 1; 4 to 11 weeks) were used to assess a possible limitation in phosphorus of zooxanthellae and to complement data on the effect of phosphate enrichment on calcification and elemental composition of the tissue in the scleractinian coral Stylophora pistillata. Phosphate addition mainly affected the coral symbionts. Indeed, at 2.5 μmol L− 1 P-enriched, zooxanthellae had a greater photosynthetic efficiency, their intracellular carbon and nitrogen contents increased by 70% and their phosphorus content by 190%, while their specific growth rate increased by 18%. C:P and N:P ratios in zooxanthellae were much higher than the Redfield ratios advocated for nutrient-repleted phytoplankton, and decreased with phosphate enrichment. Collectively, these results suggest a phosphorus limitation of the zooxanthellae growth in hospite. However, the increase in zooxanthellae specific growth rate did not lead to the building of a higher symbiont density, as zooxanthellae growth just matched the tissue and skeletal growth of the enriched corals. Benefits of phosphate supplementation were thus not substantial enough to lead to the building of higher zooxanthellae density and to their balanced growth, which suggests that symbiont growth was likely limited by another nutrient as well, probably nitrogen. At the host level, there were no changes in the elemental composition or in the protein levels, while skeletal growth rate increased by 31% between unenriched and 2.5 μmol L− 1 P-enriched corals. Phosphate-enriched corals also incorporated 1.7 times more phosphorus into their skeleton than did unenriched corals. These results evidenced that zooxanthellae and the skeleton are the two accumulation sites of inorganic phosphorus within the symbiotic association.Ecologypm2502Lamont-Doherty Earth ObservatoryArticlesNative forest tree conservation in tropical agroforests: Case study of cacao farms in the Atlantic Forest of southern Bahia, Brazilhttps://academiccommons.columbia.edu/catalog/ac:141928
McGinty, Meghan Michelinehttp://hdl.handle.net/10022/AC:P:11795Fri, 11 Nov 2011 14:24:13 +0000Agroforests are model systems for ecological conservation in tropical agricultural landscapes because they integrate biodiversity conservation and rural livelihoods. Whether agroforests are long-term solutions for conserving biodiversity in agricultural landscapes may depend sapling regeneration of native forest trees in agroforests. In this dissertation, I ask two main questions: are native forest trees regenerating in agroforests and if so, what are the ecological and social drivers? I tested the influence of potential seed sources from both the landscape and parent trees found in the agroforest. I also examined how a set of social factors affected native forest tree regeneration. The social drivers I tested include tree management and use, land tenure and state-restricted rights to harvest native timber. I found that a number of native pioneer species are regenerating at relatively high frequencies and abundances. I also found that many secondary native forest tree species are also regenerating although their sapling are found less frequently and at lower abundances. Most primary forest tree species present as adults are not regenerating and lacked sapling in the agroforests. The influence of the ecological factors was limited. The main drivers of native forest tree regeneration on farms are the understorey management and the rural extension services that assisted farms obtain state-restricted rights.Ecology, Biology, Environmental lawEcology, Evolution, and Environmental BiologyDissertationsHabitat modification and gene flow in Saimiri oerstedii: Landscape genetics, intraspecific molecular systematics, and conservationhttps://academiccommons.columbia.edu/catalog/ac:137457
Blair, Mary Elizabethhttp://hdl.handle.net/10022/AC:P:10937Thu, 18 Aug 2011 15:42:21 +0000Habitat modification, when it results in population fragmentation, often results in the loss of genetic diversity due to reduced gene flow, inbreeding, and genetic drift. However, the severity of these effects depends on how diminished dispersal and gene flow become between patches of suitable habitat. An empirical understanding of how habitat change affects dispersal and gene flow within and among patches is essential to predict the effects of increased habitat modification and landscape change on population persistence and processes of divergence. Recent studies in landscape ecology suggest that our understanding of dispersal in a heterogeneous landscape will improve by explicitly considering the heterogeneity of matrix habitats, or unsuitable habitats between patches of suitable habitat. In this dissertation, I describe population genetic structure and dispersal patterns in the Central American Squirrel Monkey (Saimiri oerstedii, Primates: Cebidae), a New World primate threatened with extinction and living in a heterogeneous, human-modified landscape, using analyses that explicitly consider matrix heterogeneity. I focus on the more endangered S. o. citrinellus, whose already restricted distribution in the Central Pacific region of Costa Rica has undergone considerable anthropogenic modification since the early 1900s. I collected non-invasive fecal samples from S. o. citrinellus across the Central Pacific region, obtaining full genotypes from 233 individuals. I also obtained 11 samples from S. o. oerstedii in the Southern Pacific region of Costa Rica from a collaborator, as well as fine-scale landscape data for the Central Pacific. I analyzed the data using molecular systematics, population genetics, and landscape genetic techniques. In this dissertation, first I explore whether molecular genetic support exists for the subspecies distinction between S. o. citrinellus and S. o. oerstedii. Second, I describe population genetic structure and recent migration patterns within S. o. citrinellus using traditional population genetic methods and Bayesian models. I also compare population genetic structure among males versus females to test for sex-biased dispersal patterns in S. o. citrinellus. Then, using landscape genetic approaches, I describe the relationship between landscape heterogeneity and genetic structure in S. o. citrinellus, and inferred which matrix habitats are costly to dispersal. Finally, I offer explicit recommendations for the conservation management of S. oerstedii. My results provide genetic support for S. o. citrinellus and S. o. oerstedii as separate taxa referred to as subspecies. Also, I found evidence of population genetic structure in S. o. citrinellus, with two genetically distinct populations and lower genetic diversity in the western population. I did not find genetic evidence for female-biased dispersal in S. o. citrinellus as expected. Instead, my results suggest that both sexes disperse, with males dispersing over longer distances. The landscape genetic analysis suggests that landscape heterogeneity is important in determining local population genetic structure in S. o. citrinellus in the Central Pacific region of Costa Rica. Specifically, oil palm plantations are moderate barriers to gene flow between populations, but not other matrix habitats. However, these inferences are specific to the composition and configuration of the Central Pacific landscape, and should not be generalized to all S. oerstedii populations. This study generated important information for conservation management. Based on my results, I recommend that conservation managers house the two S. oerstedii subspecies separately in captive facilities, and only transfer, reintroduce, or translocate among groups of the same subspecies. However, transfers, reintroductions, or translocations of either males or females are both likely to be successful for S. o. citrinellus in the Central Pacific region, pending further behavioral study. I also recommend that, in order to augment dispersal to the isolated western population of S. o. citrinellus, conservation efforts should focus on building biological corridors through or around adjacent oil palm plantations. Also, managers should prioritize the maintenance of existing forest connectivity in the Central Pacific region. The results also have important implications for future studies of evolutionary and ecological processes in heterogeneous landscapes. This study contributes to a growing body of research that finds differences in dispersal patterns among local primate populations of the same taxon. My results suggest that predictive models for variation in dispersal patterns should consider both variation among the environments of local populations within a species and temporal variation in local environments (e.g. recent habitat disturbance). Finally, this dissertation also supports the idea that matrix heterogeneity should be considered explicitly in studies of dispersal and gene flow, as opposed to assuming that all non-suitable habitats have a uniform effect on these processes. In the future, agent-based simulation approaches combined with ecological niche models and data on adaptive genetic diversity could expand upon this work to inform predictive models for population divergence and speciation under different climate and landscape change scenarios.Biology, Conservation biology, Ecologymeb2127Ecology, Evolution, and Environmental Biology, Biological Sciences, Anthropology, Earth and Environmental SciencesDissertationsThe Effectiveness of Protected Areas in Central Africa: A Remotely Sensed Measure of Deforestation and Accesshttps://academiccommons.columbia.edu/catalog/ac:131468
Rogers, Jessicahttp://hdl.handle.net/10022/AC:P:10247Fri, 29 Apr 2011 17:58:40 +0000For protected areas that are extensively forested, the rate of deforestation is one indicator of the integrity of the protected area, and the effectiveness of protected area management. The goal of this study was to examine the deforestation rate in protected areas in Central Africa. Using remote sensing techniques, I measured levels of deforestation in 87 protected areas in five countries in Central Africa from 1990-2000. To examine possible causes of deforestation I also measured the level of access in these protected areas. A lack of access to remote areas can limit deforestation, forest degradation, and the resulting loss of biodiversity while decreasing development in rural areas. Access was defined either as natural (rivers) or constructed (e.g. roads or transmission lines). The annual net deforestation rate for protected areas in Central Africa, among the protected areas studied, was 0.05%. This is lower than the annual rate of forest loss found by other studies for the entire Congo Basin forest. Based on the rates of deforestation in the entire Congo Basin and the assumption that protected areas are trying to avoid deforestation, this suggests that Central African protected areas may be effective safeguards against deforestation. Five of the 87 protected areas exhibited zero deforestation, while one forest reserve, Kaga Bandoro in the Central African Republic, showed a five percent net increase in forest cover since 1990. Cameroon's protected areas had significantly higher levels of deforestation than those in the other countries in Central Africa. Within protected areas in each country studied there was a similar level of reforestation of 5%. Deforestation in a 10km area around protected areas was not significantly higher than that found within the protected areas. Protected areas that border other protected areas had significantly lower levels of deforestation than protected areas that were isolated from each other. The increased disturbance caused by increasing access to the forest seems to be of an ephemeral nature, initially resulting in forest loss, but leading to reforestation. There was no difference in deforestation rates when a road or river bordered a protected area, or crossed through a protected area. Only the density of roads or rivers had an effect on the deforestation rates. The secondary impacts of human use on both the forest structure and the wildlife inhabiting the forest are likely to be detrimental, and worthy of further study.Environmental science, Conservation biology, Ecologyjer2103Ecology, Evolution, and Environmental Biology, International and Public AffairsDissertationsLinking plant traits and herbivory in grassland biodiversity-ecosystem functioning researchhttps://academiccommons.columbia.edu/catalog/ac:131411
Flynn, Dan F. B.http://hdl.handle.net/10022/AC:P:10230Thu, 28 Apr 2011 15:29:22 +0000Increased availability of data on morphological, physiological, and behavioral traits of species has improved understanding of the processes driving community assembly and the consequences of community disassembly for ecosystem functioning. In addition, there has also been a call for advancing the multitrophic view of biodiversity- ecosystem functioning. Here I propose a trait-based framework to merge plant-herbivore interactions with biodiversity-ecosystem function relationships. This framework links plant growth and defense strategies, herbivore feeding preferences, and primary production in terrestrial plant communities. I empirically tested these proposed linkages in laboratory and field experiments carried out in the understudied grasslands of Inner Mongolia, China. I found that a dominant generalist grasshopper Oedaleus asiaticus exhibits feeding preference for plants of high palatability when equally available, but in the field feeds on nearly any graminoid which is dominant. This behavior potentially allows subdominant plants to coexist, maintaining plant diversity. To link feeding behavior to consequences for plant communities, I carried out detailed measurements of plant morphological and physiological traits in the field and experimentally manipulated grasshopper feeding intensity. Using a novel analytical tool, I found that plant communities in these grasslands exhibit high niche overlap, regardless of intensity of herbivory by grasshoppers or sheep. This result indicates that environmental filtering structures these communities more than limiting similarity. Extending the use of traits beyond the study system in Inner Mongolia, I test the how both functional and phylogenetic diversity explain the biodiversity effect on grassland ecosystem functioning. The promise for merging tools from evolutionary biology and functional ecology is great, as these diversity metrics provide superior explanatory power in a meta-analysis of biodiversity experiments. Future work should be addressed at clarifying which functional traits are most strongly reflected in measures of phylogenetic diversity, including strategies of compensating for or avoiding herbivory.Ecology, Plant biology, Biologydff2101Ecology, Evolution, and Environmental BiologyDissertations